The listening environment, including speakers, room geometries and materials, furniture, and so forth can have an enormous effect on the quality of audio reproduction. Recently it has been shown that one can employ relatively simple digital filtering to provide a much more faithful reproduction of audio as it was originally recorded in a studio or concert hall (see, e.g., http://www.princeton.edu/3D3A/BACCH_intro.html). In fact, it is possible to produce three-dimensional sound using two speakers by using active cross-talk cancellation. In virtually any kind of listening environment, one can also compensate for speaker mismatches, and variability in the room arrangement, using phase and amplitude equalization. Today, however, with music being highly portable with mp3 players, mobile phones, and the like, and with music available through Internet cloud services, consumers bring their music into many different listening environments. It is rare that these environments are configured in an optimal way, and so it is advantageous to have a simple but effective method of calibrating digital filters for use with portable devices such as mobile phones, that can be used with various kinds of audio playback devices, such as automobile audio systems, phone docking systems, Internet connected speaker systems, and the like. In addition, audio that is played on laptops, TVs, tablets, etc. can also benefit from precise digital equalization. Systems and methods are presented herein for facilitating cost-effective calibration of filters for, e.g., correcting room and/or speaker-based distortion and/or binaural imbalances in audio reproduction, and/or for producing three-dimensional (3D) sound in stereo system environments.